1. Field
The present disclosure relates to a secondary battery and method of manufacturing the same.
2. Description of Related Art
Some secondary batteries, for example, a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, may have a lighter weight and a higher energy density than other various existing batteries. As a result, nonaqueous electrolyte secondary batteries have been used as a so-called “portable power supply” for a PC, a portable device, or the like or as a power supply for a vehicle. It is expected that light-weight lithium ion secondary batteries capable of obtaining a high energy density will be increasingly used as a high-output power supplies for driving a vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a plug-in hybrid vehicle (PHV).
Some secondary batteries have a structure in which a wound electrode body is accommodated within a battery case. The wound electrode body may be obtained by laminating and winding an elongated positive electrode sheet, an elongated negative electrode sheet, and an elongated separator to obtain a wound laminate. A metal case may be used as a battery case. In the wound electrode body, current collector portions are provided at both end portions in a width direction (a direction perpendicular to a longitudinal direction). In the current collector portions, a positive electrode and a negative electrode may be exposed. Therefore, when a battery case is formed of metal, for example, as described in Japanese Patent Application Publication No. 2013-222504 (JP 2013-222504 A), an electrode body is covered with a rectangular-cuboid shaped insulating film to insulate the battery case and the electrode body from each other. In order to prevent the electrode body from moving into the battery case due to vibration of a vehicle, the insulating film may be fixed to the battery case by thermal welding.